const Koa = require("koa");
const app = new Koa();

app.use(async (ctx,next) => {
    console.log("hello world1");
    await next();
    console.log("hello world2");
})

app.use(async (ctx,next) => {
    console.log("我是一个中间件");
})

app.listen(3000,() => {
    console.log("server is running")
});